attach or overwrite media doesn't works as expected

[Tiemo]

Hello,
BackupExcec 12, Rev 1364: Sorry, if I don't hit the exact Symantec expressions, they are free translations from my german system. I don't know if I have misunderstandings or misfunctions

Scenario:
I have a son-father-grandfather backup concept with 3 rotating discs, one per week. Each week I want to start with a full backup and add differential backups the other days of the week.
In the BE media section I have two definitions
1. "Data-Full" with overwrite protection: 2 weeks and Appending: unlimited
2. "Data-Diff" with overwrite protection: 1 week and Appending: unlimited
In the order setup I have two definition
1. "Data-Full", when order starts: overwrite media
2. "Data-Diff", when order starts: attach to media or overwrite

The problems:
1. The Data-Full backup doesn't delets the complete media when starting (what I would like). It starts to overwrite one old file after the other, so that the full backup is chopped into several pieces. Probably not a problem, but this way there are left always old files on the disc if there is enough space left. My workaround is, that I delete the entire disc manually except the changer.cfg and folder.cfg  before starting a new week.
2. The Data-Diff delets always the differential backup from the last day, so that there is only the full backup and the current differential backup from last night on the disc, though there is enough free space. What I would like (and expected) is, that I have have at the end of the week the full backup and a differential backup of every day, so that I could restore every single day, if I would whish. Now I can only restore the first or the last day of the week.

Is the fault in my brain or in the options I choose?
Thanks for any hint
Tiemo

[Tiemo]

Any ideas?
I really don't know if I am on the wrong lane with what I expect or if I just set the wrong options?
Any hint welcome
Thank you

[Ben_L_]

Change your append period to 0 hours.  With an append period of unlimited, this will allow the files to continue to append and each time this happens the over protection period gets reset.  This will also make so whenever a backup is run it creates a new file, you are going to use the disk space regardless of if your appending to files or creating new ones.  Your stategy will work alot easier of you only do overwrites.  Also with 0 append period, when the overwrite protection period runs out the files will automatically get overwritten so you should not have to manually delete the files.

[Tiemo]

Hello Ben

hmm, the docs say to "appending period" it is the period where I can add files to the media. And what I want is  to have one full backup and 6 differential backups (one week) on one backup media. For my understanding BE would only write one backup to one media (the full backup) if I set this option to 0 and would use for the first differential a new media.  Is the german translation of the docs not good or is it still my understanding?

Thank you for your helpful explanation

[Colin_Weaver]

OK your problem is that your differential and full backups go to diifferent media sets - an individual piece of media can only be be in one set at a time so to achieve writing the Differential backup jobs to the same tape as the full backup job they would have to use the same set.

[Ben_L_]

I missed that before, what Colin said is correct.  You need to have both backup jobs using the same media set.  Also to have them all go to the same file (i.e. 1 full backup and 6 diff backups) then you will need to set your append period for 6 days.  This will keep the next full from writing to that file.  Also you will need to set the max size of the BKF files to be large enough to hold the fulls and the differentials.

[Tiemo]

That sounds as making sense, I will give it a try!
Thanks Colin and Ben for your advice